Scientists used a genetically engineered vaccine to successfully eradicate high-grade precancerous cervical lesions in nearly one-half of women who received the vaccine in a clinical trial. The goal, said the scientists, was to find nonsurgical ways to treat precancerous lesions caused by human papillomavirus (HPV). Their work was published in The Lancet (2015; doi:10.1016/S0140-6736(15)00239-1).

"Every standard therapeutic option for women with these lesions destroys part of the cervix, which is particularly relevant for women of childbearing age, who may then be at risk for preterm birth due to a weakened cervix," said first author Cornelia Trimble, MD, professor of gynecology and obstetrics, oncology, and pathology at the Johns Hopkins University School of Medicine in Baltimore, Maryland.

"A vaccine able to cure precancerous lesions could eventually be one way women can avoid surgery that is invasive and can also harm their fertility."

High-grade cervical lesions, termed CIN2/3, occur most often in women age 40 years or younger, according to Trimble. Because the lesions can progress to cancer, they are usually removed by surgery, freezing, or laser.

The procedures are successful in removing the precancerous areas in approximately 80% of women. Less troublesome lesions, called low-grade dysplasia, are usually monitored by physicians rather than immediately removed because they pose less of a

For the study, the scientists used a vaccine engineered to teach immune system cells to recognize precancerous and cancerous cells. The vaccine, given by injection into the arm, is made by Inovio Pharmaceuticals Inc, which funded the clinical trial, and whose employees co-authored the report with Trimble.

Between 2011 and 2013, the scientists recruited 167 women, ages 18 to 55 years, with newly diagnosed, high-grade precancerous cervical lesions. The women were randomly assigned to receive either three doses of the vaccine or saline injections over a 12-week period.

Of 114 women who received at least one vaccine dose, 55 (48.2%) had a regression of their precancerous lesion, meaning their lesions disappeared or converted to low-grade lesions, compared with 12 of 40 (30%) who received saline injections.

Of the 114 vaccinated women, 107 received all three vaccine doses, and lesion regression occurred in 53 of them (49.5%). Of the 40 women in the saline group, 36 received all three injections with tumor regression occurring in 11 of them (30.6%). Thirteen women dropped out of the study after enrollment.

Among the women who completed all three injections, scientists could find no trace of HPV in the cervixes of 56 of the 107 vaccinated women, compared with only 9 of 35 saline recipients.

"In many of these women, the vaccine not only made their lesions disappear, but it also cleared the virus from their cervix," says Trimble. "In most unvaccinated patients whose lesions went away, the virus was still present, and many still had low-grade lesions."

Trimble says clearance of the virus is a significant bonus from receiving the vaccine because persistent HPV infection is a major risk factor for recurrence of cervical lesions.

"This is a great first step," said Trimble. "We showed that the vaccine may enable an immune response in a person whose immune system was initially not adequately engaged or was hampered in some way so as to let the lesion occur."

"It typically takes about 10 or more years for precancerous cells to become cancer, so there is a window of opportunity to intervene with nonsurgical approaches to reverse the process of viral-associated cancers," said Trimble.